1. Field of the Invention
This invention relates generally to the field of torque sensors and angular position sensors and more particularly pertains to the use of such sensors in the testing of automotive automatic transmissions.
2. Description of the Prior Art
After an automotive automatic transmission is assembled, the throttle valve mechanism and the gear selector mechanism of the transmission are tested to assure that the angular positions of the respective control levers correspond to the desired transmission function and that the torque required to move the levers between the various positions is within an acceptable range of tolerance. In conventional test systems for controlling movement of the transmission mechanism, rack and pinion gears are used to transmit power to the shift lever and gear selecting lever. Torque transmitted through the rack and pinion system is measured and the angular positions of the levers are determined from the angular position of the pinion with respect to a reference position. This drive system has inherent capacity to produce inaccurate results because backlash necessarily present in the rack and pinion system adversely affects the measurement of angular position. Consequently, the angular position of the control levers and the torque required to move them cannot be determined with acceptable precision. Furthermore, because the support for the various shafts driven by the rack and pinion system require an unacceptably large amount of friction, the measured torque is more than the torque required to move the gear selector mechanism and throttle mechanism.